The present invention relates to a digital image recording and reproducing apparatus for recording digital images in and reproducing digital images stored in an optical disk or the like, and more particularly to a digital image recording and reproducing apparatus for rapidly browsing through still images that are successively displayed to a user, who retrieves a desired still image therefrom.
Write-once-read-many (WORM) optical disks on which the user can record data represent a large-capacity digital recording medium. For example, the WORM optical disk with a diameter of 5 inches has a recording capacity of 320 Mbytes on one side alone.
A 5-inch optical disk has a track extending spirally from the inner periphery to the outer periphery of the disk and having about 20,000 turns. The track is circumferentially divided into 32 sectors. A track turn has a first recording pit group with a leading address given to its leading end and a second recording pit group with a leading address given to its leading end. Similarly, leading addresses are given to the leading ends of each succeeding recorded pit group. Each sector of one track turn has a recording capacity of 512 bytes.
If television images are to be recorded as still image data on the optical disk, then about 1,000 sectors are required to store one frame of image, and data on about 700 still images can be recorded on one optical disk.
A conventional still image recording and reproducing apparatus for reproducing recorded still images from such an optical disk employs 8 bits for quantizing image data. Therefore, the image memory used in the apparatus has a large storage capacity, and requires a long time to reproduce an entire still image.
More specifically, when still images are successively displayed at a high speed for image retrieval, the still images are roughly checked and browsed by a user until a desired still image is recognized. However, the conventional still image recording and reproducing apparatus takes too a long time to reproduce one still image, and as a result, it is time-consuming to browse all the still images for image retrieval.